The recent tremendous progress in genomics provides biomedical science with a remarkable opportunity to unravel the complex interactions between genetic variation and environmental variables (Gene and Environment Interactions or GEI) responsible for common complex human disease. Some of the advances contributing to this opportunity include availability of high quality whole genome sequence from >30 vertebrate species including our own plus a growing catalog of human genetic variation provided by HapMap and the fledgling projects aimed at understanding common structural variation. This opportunity is accompanied by a host of challenges including optimal study design, selection and utilization of a genotyping platform appropriate for each study, generation of high quality genotypic data and efficient and comprehensive downstream data analysis for genome wide association studies. The Johns Hopkins University Center for Inherited Disease Research (JH/CIDR) proposes to provide state-of- the-art whole genome association SNP genotyping for 12,000 samples over 3 years that will capture at least 80% of the genetic variation in the relevant study population as well as flexible regional genotyping that will enable custom fine mapping of genomic regions shown to harbor genes contributing risk for complex traits. We will also provide ancillary services as needed for individual projects including DNA isolation, whole genome amplification, assistance in study design and data analysis and provision of genotypic data in study-specific formats to the investigators and to the specified central database. Finally, we will work with the GEI Coordinating Committee in the planning and performance of this project. To achieve these aims we will build on the ten-year experience of JH/CIDR releasing more than 30 million high quality STRP and 1.2 billion high quality SNP genotypes for 128 projects and ~165,000 DNA samples. In this effort, we have interacted with >125 investigators providing genetic epidemiology expertise to assist with study design and analysis. Additionally, we will continue our commitment to evaluation of the rapidly evolving technological environment to provide the genetics community with the most robust, reliable and cost-effective genotyping platforms available. We will also take advantage of the rich scientific environment provided by the Johns Hopkins McKusick-Nathans Institute of Genetic Medicine and the greater Johns Hopkins School of Medicine and School of Public Health environment to maximize the broad expertise we bring to bear on this project.